Classical Mechanics Answers

A 18.5 cm long probe used in a diagnostic process consists of a thin 16.0 cm long plastic rod with a cross-sectional area of and a 2.50 cm long nylon tip. Both the rod and tip have a cross-sectional area of 0.955×10−6 m2.

The (compressive) Young's modulus of plastic is 3.51 GPa, and the compressive Young's modulus of the nylon used is 2.02 GPa.

The instrument is pressed against a bone with a compressive force of 105 N. What is the change in length of the instrument? (to 2 s.f and in mm)

A reckless hunter is on a boat that is stationary in the middle of a lake.

They fire their gun horizontally 10 times. Each time they fire, a 12 g bullet leaves the gun at a speed of 410 m s−1.

What is the speed of the boat after they have finished firing their gun if the total mass of the boat, hunter, and gun is 150 kg? (in m s−1 to 2 s.f)

Assume no drag forces from the water.

A star rotates with a period of 30 days about an axis through its center. The period is the time interval required for a point on the star’s equator to make one complete revolution around the axis of rotation. After the star undergoes a supernova explosion, the stellar core, which had a radius of 1.0 x 10^4 km, collapses into a neutron star of radius 3.0 km. The period of rotation of the neutron star is 0.23 s. Calculate the work done by the 'supernova' forces per kg of star mass. (MJ/kg = 10^6 J/kg)

1. When visiting the Italian town of Pisa, young physics student Isaac Galilei drops an apple with a weight of 2.0 N from the city's famous leaning tower. The apple falls 56m to the ground. First question: Ignoring air resistance and other subtle effects, how long does it take the apple to fall to the ground? The apple takes _____ s to fall to the ground.

Q5.A system of N spin-1/2 particles, each with magnetic moment m, is in presence of a
magnetic field B. Initially, all the magnetic dipoles are oriented along the direction of the
magnetic field. If the energy of the system is increased by ΔE = + mB, what is the change
in entropy of the system?

Q.Consider an isolated system of ten particles undergoing random collisions, and confined
to a cubical box of volume V. Compare the probabilities that all the particles are in the left
half vs five particles are in the left half. Is this in contradiction with the principle of equal
a-priori probabilities.

a particle P moves in a straight line . the velocity vms-1 at time t s is given by
v=5t(t-2) for 0<=t<=4
v=k for 4<=t<=14
v=68-2t for 14<=t<=20
where k is constant
1) find k.
2)sketch the velocity time graph for 0<=t<=20
3)find the set of values of t for which the acceleration of P is positive
4)find the total distance travelled by P in the interval 0<=t<=20

assignment 1} add two vectors on a piece of paper or graph paper A] vector 1: 10 Newtons North. B] vector 2: 5 N WSW

This web site https://www.geogebra.org/m/ZeZjAfta is for double incline plain calculations. It list a rope tension (t = 22.5 s). I need to know how much force in poundage that is? I have a screen shot of the calculation. I see no ability for an attachment. I this example the tension is increasing as one weight pull the other down the incline?

A small ball is released from rest and falls on the horizontal platform which is
descending with a constant speed 7 1ms-1 .Given that the ball is 12m above the
platform at the instant of release. Calculate the time that elapses before the ball
hits the plat form.